Abstract
The Cambrian Jiulaodong Formation of the Wei-201 well block in the Sichuan Basin was investigated for shale gas potential. In the subsurface, the thermally mature formation attained a stable thickness of 234 m encompassing an area of approximately and representing a potential gas resource. The total gas content measurements from canistered samples was more than the estimated total gas storage capacity of the free gas, absorbed gas, and gas dissolved in water and in oil. The canister gas content ranged between 0.971 and and averaged . The average estimated gas in place was 2.5 billion cubic meters for the formation in the Weiyuan area. Reflectance measurements for thermal maturity range between 2.60% and 3.06% and average 2.84%. The results of our total organic carbon content (TOC) content analysis conducted on the core shale samples indicate that the TOC content of the formation ranges from 0.87% to 3.57% and averages 2.2%. The mineral composition of marine mudstone formation of the Jiulaodong shale is relatively consistent. Brittle mineral content increases with organic carbon content and is approximately 32%–43%, of which quartz content is 29%–40% with a very low amount of clay mineral as the mixed layer. The amount of illite-smectite ranges from 0% to 1% and the brittleness index range from 37% to 62% and average 57.1%. The Cambrian Jiulaodong Formation ha very good petroleum-source rock potential due to its average TOC content of greater than 2%, average canister gas content of , good type I kerogen, high maturity with average 2.84% of source rocks that are characterized by a fairly high abundance of organic matter increasing from top to bottom and a large thickness of 234 m. Natural fractures, cracks, and pores developed in the Jiulaodong Formation also provide space for shale gas storage, and its average brittleness index is greater than 57%, which is good for fracability.
References
- , 1986, Notes on sedimentary basins in China — Report of the American sedimentary basins delegation to the People’s Republic of China: U.S. Geologic Survey Open-File Report, 107,
86–327 . - , 2001, The Lewis shale, San Juan Basin: Approaches to Rocky Mountain tight shale gas plays:
Petroleum Technology Transfer Council Southwest Region Workshop , http://pttc.org/workshop_summaries/502.pdf. - , 2009, The geomechanics of shale play: What makes a shale prospective!
SPE Eastern Regional Meeting . - , 2006, Shales require creative approaches: AAPG Explorer, 27,
6–10 . - , 2012, Introduction to vitrinite reflectance as a thermal maturity indicator: AAPG Search and Discovery.
- , 2014, Reservoir evaluation of the Lower Silurian Longmaxi Formation shale gas in the southern Sichuan Basin of China: Marine and Petroleum Geology, 57,
619–630 , doi:10.1016/j.marpetgeo.2014.07.008 .MPEGD8 0264-8172 - , 1986, Calculation of petroleum masses generated and expelled from source rocks: Advances in Organic Geochemistry, 10,
235–245 , doi:10.1016/0146-6380(86)90026-4 . - , 2002, Fractured shale-gas systems: AAPG Bulletin, 86,
1921–1938 .AABUD2 0149-1423 EIA/ARI study , 2013, EIA/ARI World shale gas and shale oil resource assessment: Advanced Resources International Inc.- , 2011, Predicting fracability in shale reservoirs: AAPG Search and Discovery.
- , 1985, La pyrolyse Rock-Eval et ses applications: Revue de l’Institut Français du Pétrole, 40,
563–579 . - , 1977, Methode rapide characterisaion des roches meres de leur potential pétrolier et de leur degree d’evolution: Revue de l’Institut Françe Pétrole, 32,
23–42 . - , 2013, Mechanisms of shale gas storage: Implications for shale gas exploration in China: AAPG Bulletin, 97,
1325–1346 , doi:10.1306/02141312091 .AABUD2 0149-1423 - , 1975, Organic metamorphism and the generation of petroleum: AAPG Bulletin, 59,
986–996 .AABUD2 0149-1423 - , 1988, Huanan Alps, not South China platform: Scientia Sinica (Series B), 31,
109–119 . - , 2012, Shale gas generation and potential of the Lower Cambrian Qiongzhusi Formation in the Southern Sichuan Basin, China: Petroleum Exploration and Development, 39,
75–81 , doi:10.1016/S1876-3804(12)60017-2 . - , 2014, China organic-rich shale geologic and special shale gas production issues: Journal of Rock Mechanics and Geotechnical Engineering, 6,
196–207 , doi:10.1016/j.jrmge.2014.03.002 . - , 2011, China begins to tap its shale gas, despite daunting technological, environmental hurdles: Environment and Energy Publishing.
- , 1991, The Sichuan Basin, Southwest China: A Late Proterozoic (Sinian) petroleum province: Precambrian Research, 54,
45–63 , doi:10.1016/0301-9268(91)90068-L .PCBRBY 0301-9268 - , 1918, The adsorption of gases on plane surfaces of glass, mica, and platinum: Journal of American Chemical Society, 40,
1361–1403 , doi:10.1021/ja02242a004 . - , 2012, Stratigraphic division and correlation and sedimentary characteristics of the Cambrian in central-southern Sichuan Basin: Petroleum Exploration and Development, 39,
725–735 , doi:10.1016/S1876-3804(12)60097-4 . - , 1993, Matrix permeability of gas productive shales:
SPE Annual Technical Conference and Exhibition ,261–270 . - , 2008, Petroleum geology of the Puguang sour gas field in the Sichuan Basin, SW China: Marine and Petroleum Geology, 25,
357–370 , doi:10.1016/j.marpetgeo.2008.01.010 .MPEGD8 0264-8172 - , 1991, Gelologic influences on the location and production of Antrim Shale gas, Michigan Basin:
Proceedings of Society of Petroleum Engineers, Rocky Mountain Regional; Low Permeability Reservoirs Symposium and Exhibition ,511–519 . - , 2004, Uncertainty in sorption isotherm measurements:
Proceedings of the 2004 International Coalbed Methane Symposium ,411 . - , 1997, Coalbed reservoir gas-in-place analysis: Gas Research Institute Report GRI-97/0263.
- , 2005, Mississippian Barnett Shale, Forth Worth Basin, North-central Texas: Gas shale play with multi-trillion cubic foot potential: AAPG Bulletin, 89,
155–175 , doi:10.1306/09170404042 .AABUD2 0149-1423 - , 2010, From oil-prone source rock to gas-producing shale reservoir-geologic and petrophysical characterization of unconventional shale-gas reservoirs:
International Oil and Gas Conference and Exhibition in China . - , 1990, A practical model for organic richness from porosity and resistivity logs: AAPG Bulletin, 74,
1777–1794 .AABUD2 0149-1423 - , 1986, Guidelines for evaluating petroleum source rocks using programmed analysis: AAPG Bulletin, 70,
318–329 .AABUD2 0149-1423 - , 1993, The biomarker guide: Interpreting molecular fossils in petroleum and ancient sediments: Prentice-Hall.
- , 2007, Geologic framework of the Mississippian Barnett Shale, Barnett-Paleozoic total petroleum system, Bend Arch-Fort Worth Basin, Texas: AAPG Bulletin, 91,
405–436 , doi:10.1306/10300606008 .AABUD2 0149-1423 - , 2013, Vitrinite reflectance, thermal maturity and coal rank in Lower Cretaceous Medicine River Coals of South Central Alberta: Reflectance suppression and the role of liptinite macerals in hydrocarbon generation — Implications of CBM exploration: AAPG Search and Discovery.
- , 2008, A practical use of shale petrophysics for stimulation design optimization: All shale plays are not clones of the Barnett Shale:
SPE Annual Technical Conference and Exhibition ,11 . - , 2008, Characterizing the shale gas resource potential of Devonian-Mississippian strata in the Western Canada sedimentary basin: Application of an integrated formation evaluation: AAPG Bulletin, 92,
87–125 , doi:10.1306/09040707048 .AABUD2 0149-1423 - , 2010, Petrophysical considerations in evaluating and producing shale gas resources:
SPE Unconventional Gas Conference . - , 2013, China shale gas and shale oil resource evaluation and technical challenges:
SPE Asia Pacific Oil and Gas Conference and Exhibition . - , 2012, Seismic inversion in the Barnett shale successfully pinpoints sweet spots to optimize well-bore placement and reduce drilling risks:
82nd Annual International Meeting, SEG , Expanded Abstracts, doi:10.1190/segam2012-1266.1 . - , 2012, Organic-rich Marcellus shale lithofacies prediction by multi-class neural network classification in the Appalachian Basin: Mathematical Geoscience, 44,
975–1004 , doi:10.1007/s11004-012-9421-6 . - , 2013, Organic-rich Marcellus shale lithofacies modeling and distribution pattern analysis in the Appalachian Basin: AAPG Bulletin, 97,
2173–2205 , doi:10.1306/05141312135 .AABUD2 0149-1423 - , 1989,
Formation and development of the Sichuan Basin , in X. Zhu, ed., Chinese sedimentary basins: Elsevier,147–163 . - , 1985, Geochemistry in petroleum exploration: International Human Resources Development Corporations.
- , 2008, Petroleum systems of the oldest gas field in China: Neoproterozoic gas pools in the Weiyuan gas field, Sichuan Basin: Marine and Petroleum Geology, 25,
371–386 , doi:10.1016/j.marpetgeo.2008.01.009 .MPEGD8 0264-8172 - , 2000, Investigation of thermal maturity of lower Palaeozoic hydrocarbon source rocks by means of vitrinite-like maceral reflectance — A Tarim basin case study: Organic Geochemistry, 31,
1041–1052 , doi:10.1016/S0146-6380(00)00061-9 .ORGEDE 0146-6380 - , 1994, Static and dynamic rock mechanical properties in the Hugoton and Panoma Fields, Kansas:
SPE Mid-Continent Gas Symposium ,213 . - , 1997, Petroleum geology of China: Petroleum Industry Press.
- , 2014, Modeling free gas content of the Lower Paleozoic shales in the Weiyuan area of the Sichuan Basin, China: Marine and Petroleum Geology, 56,
87–96 , doi:10.1016/j.marpetgeo.2014.04.001 .MPEGD8 0264-8172
